This a new program project on the central theme of imaging regional myocardial and pulmonary transport, and functions and on the relationship of these functions to local, regional flows. These will be studied under normal conditions in order to gain understanding of the several-fold range of normal regional flows in heart and lung, and in ischemia or occlusion an during reperfusion. The five projects include continuations or offshoots of four well-developed research programs and a new one on myocardial stunning. In addition to standard physiological methods, the projects exploit the use of non-invasive methods, positron emission tomography (PET), single photon emission completed tomography (SPECT) and nuclear magnetic resonance (NMR). The projects concern: (1) Cardiac Metabolism/Flow (Bassingthwaighte): Assessment of the influence of local metabolism of lipids and O2 on regional flows in the normal heart with its 5-fold range of local flows, and the perturbation of the relationship in abnormal vasomotor states. (2) Pulmonary Blood and Gas Flow (Robertson): Quantitation and evaluation of the anatomic and physiologic determinants of the heterogeneity of pulmonary blood and gas flow as they relate to overall pulmonary gas exchange. (3) Cardiac Energetics/Lipids/Mechanics (Wesbey): Determination of the role of regional myocardial high energy phosphates and lipids in the recovery of regional mechanical function following transient ischemia ("stunning"). (4) Lung Ischemia (Modell): Mechanisms of lung injury during pulmonary artery obstruction. (5) Cardiac Ischemia (Caldwell): Determination of the relationship between regional lipid metabolism in hypoxia and ischemia, as measured by PET and SPECT, and the recovery of regional function. These five projects are served by core programs on imaging (radiopharmaceutical synthesis, imaging by positron emission and single photon emission computed tomography), and analysis (of data on regional tissue tracer content as a function of time), an animal physiology laboratory, and administration. The program brings together investigators from Cardiology, Respiratory Disease, Radiology, Radiation Oncology, Pathology, Anesthesiology, and Bioengineering, sharing a common set of goals and approaches to gaining fundamental understanding of regional flows, metabolism, and function in the heart and lung in the normal state and during ischemia and reperfusion.